184 



LYCOPODIALES 



[CH 



Isoetes (cf. fig. 133, E). Beyond the distal end of the sporangium 

 the sporophyll becomes broader in a horizontal plane and is 

 bent upwards as a lanceolate limb ; it may also be prolonged a 

 short distance downwards as a bluntly triangular expansion. 



Fig. 189 is an accurate representation of a transverse 

 section, 6 mm. in diameter, of what is no doubt the apical 

 portion of a Lepidostrobus from the Coal-Measures of Shore, 

 Lancashire. The section cuts across the upturned free laminae 

 above the level of the apex of the cone-axis. Each lamina 



Fig. 189. Lepidostrobus. Section through the apical region of a cone above 

 the axis. (Manchester University Collection.) 



contains a small vascular bundle composed of a few tracheae and 

 some thin-walled cells surrounded by delicate mesophyll tissue. 

 Immediately in front of the distal end of a sporangium a 

 small ligule is borne on the upper face of the sporophyll 

 (fig. 191, A, B, I) occupying the same position as in Selaginella 

 (cf fig. 131, F). Strands of vascular tissue pass in a steeply 

 ascending course from the xylem to the pedicels of sporo- 

 phylls, finally curving upwards and ending in the upper limb. 



